Catalyst for vinyl compounds and process for production of vinyl polymers

ABSTRACT

The catalyst for polymerizing vinyl compounds according to the present invention comprises (A) a complex of Group 4 to 10 transition metal of the Periodic Table, (B) a clay, clay mineral or ion-exchangeable layered compound, and (C) at least one aluminoxy compound represented by Formula (1):  
                 
 
     wherein a plurality of R groups are each independently C 1-10  hydrocarbon group and at least one of the R groups is a hydrocarbon group having 2 or more carbon atoms; and x is an integer of 2 or more. By using the Group 4 to 10 transition metal complex and the clay, clay mineral or ion-exchangeable layered compound in combination with the specific aluminoxy compound, vinyl polymers are produced at a high efficiency. Also, the catalyst for producing α-olefins according to the present invention comprises (A′) a complex of Group 8 to 10 transition metal of the Periodic Table, (B′) an organic compound-modified clay, clay mineral or ion-exchangeable layered compound, and (C′) at least one aluminoxy compound represented by Formula (2):  
                 
 
     wherein a plurality of R groups are each independently C 1-10  hydrocarbon group and at least one of the R groups is a hydrocarbon group having 2 or more carbon atoms; and y is an integer of 2 to 4. Since the organic compound-modified clay, clay mineral or ion-exchangeable layered compound absorbs other catalyst components between layers thereof, the elution of the catalyst components into liquid phase is effectively prevented, thereby facilitating the separation of the catalyst from a reaction product.

TECHNICAL FIELD

[0001] The present invention relates to a catalyst for polymerizingvinyl compounds and a process for producing vinyl polymers using thecatalyst, and more particularly, to a catalyst for polymerizing vinylcompounds which is capable of efficiently producing vinyl polymershaving terminal vinyl bonds, and a process for producing vinyl polymersusing such a catalyst.

BACKGROUND ART

[0002] Metallocene catalysts (Kaminsky catalysts) used together withmethylaluminoxane (MAO) as a co-catalyst have been found to be useful ascatalysts for the polymerization of olefins, and have been extensivelystudied. However, in order to allow the metallocene catalysts to exhibitits catalytic activity, it is necessary to use therewith a large amountof the expensive methyl aluminoxane. To solve the problem, for example,Japanese Patent Application Laid-Open No. 5-25214 has proposed to use amethylalumoxane co-catalyst supported on clay minerals (one ofsilicon-containing layered compounds) as a catalyst component forolefin-polymerizing catalyst, and specifically describes amethylalumoxane co-catalyst supported on smectite (clay minerals areused as a catalyst support). However, the preparation of such aco-catalyst inevitably requires to treat clays with a large amount ofexpensive and harmful methylalumoxane, and the obtained catalyst isstill insufficient in polymerization activity per unit quantity of thealuminum component used. In addition, U.S. Pat. No. 5,308,811, etc.,have proposed the use of clays treated with an aluminum compound such astrialkylaluminum as a co-catalyst, and specifically describes a catalystcomposition comprising a metallocene complex, clay minerals, etc.However, the catalyst composition fails to achieve a sufficientpolymerization activity for vinyl compounds only by treating clays withordinary organoaluminum compounds. WO 99/02472 describes a process forproducing α-olefins using a catalyst composed of a specific iron complexand an organoaluminum compound, and also describes the use of acidicclays such as montmorillonite as a support of activated catalysts orcatalyst precursors. However, when methylaluminoxane described as aspecific example of the organoaluminum compound is used as a catalystcomponent, the catalytic activity, especially the activity per unitquantity of aluminum, is still unsatisfactory.

[0003] Japanese Patent Application Laid-Open No. 8-295705 describes aprocess for producing α-olefins by the oligomerization of ethylene, inwhich α-olefins are separated from a reaction product to recover acatalyst and by-produced polymers. In this process, after separatingα-olefins by distillation using an evaporator, the by-produced polymerand catalyst are recovered in the concentrated liquid residue. Also,Japanese Patent Application Laid-Open No. 10-45833 describes a processin which a reaction product solution is kept at a high temperature inorder to inhibit the precipitation of by-produced polymer and facilitatesubsequent treatments. In these conventional processes, since α-olefinsare separated by distillation in the presence of the catalystcomponents, α-olefins are susceptible to side reactions such asisomerization. Further, Japanese Patent Application Laid-Open No.7-149671 describes a process in which after preliminarily separatingby-produced polymer, an ethylene oligomer (α-olefin) is separated andpurified. In any of the prior art processes, ethylene is trimerized inthe presence of a chromium catalyst to produce oligomers thereof.Further, these processes require an additional step for subjecting thecatalyst components to deactivation or deashing treatment for removalthereof. In particular, in the process described in Japanese PatentApplication Laid-Open No. 7-149671, since a homogeneous catalyst systemcomprising a chromium complex is used to enhance the catalytic activity,it is not possible to completely remove the catalyst components uponremoval of the by-produced polymer. In addition, a pyrrole compoundadded to improve the activity of the chromium catalyst is difficult toremove, resulting in failure to purify α-olefins having 8 or more carbonatoms.

DISCLOSURE OF INVENTION

[0004] A first object of the present invention is to provide a catalystfor the polymerization of vinyl compounds which is capable ofefficiently producing vinyl polymers having terminal vinyl bonds. Asecond object of the present invention is to provide a process forproducing vinyl polymers using the above catalyst. A third object of thepresent invention is to provide a catalyst for the production ofα-olefins which is readily separated from the reaction product afteroligomerization reaction. A fourth object of the present invention is toprovide a process for producing α-olefins using the above catalyst forthe production of α-olefins in which the catalyst and by-producedpolymer are readily separated from the reaction product.

[0005] As a result of the extensive studies for accomplishing the aboveobjects, the inventors have found that vinyl polymers are efficientlyproduced in the presence of a catalyst comprising (A) a complex of Group4 to 10 transition metal of the Periodic Table, (B) a clay, clay mineralor ion-exchangeable layered compound, and (C) a specific aluminoxycompound. The inventors have further found that α-olefins areefficiently produced in the presence of a catalyst comprising (A′) acomplex of Group 8 to 10 transition metal of the Periodic Table, (B′) anorganic compound-modified, clay, clay mineral or ion-exchangeablelayered compound, and (C′) a specific aluminoxy compound, and that thecatalyst is readily separated from a reaction product. The presentinvention has been accomplished based on these findings.

[0006] Thus, the present invention provides a catalyst for polymerizingvinyl compounds comprising (A) a complex of Group 4 to 10 transitionmetal of the Periodic Table, (B) a clay, clay mineral orion-exchangeable layered compound, and (C) at least one aluminoxycompound represented by the following general Formula (1):

[0007] wherein a plurality of R groups are each independently a C₁₋₁₀hydrocarbon group, and at least one of the R groups is a hydrocarbongroup having 2 or more carbon atoms; and x is an integer of 2 or more.

[0008] The process for producing vinyl polymers comprises a step ofpolymerizing at least one vinyl compound selected from the groupconsisting of olefins, styrene, styrene derivatives, acrylic acidderivatives and vinyl esters of fatty acids in the presence of thecatalyst for polymerizing vinyl compounds as defined above.

[0009] The present invention further provides a catalyst for producingα-olefins comprising (A′) a complex of Group 8 to 10 transition metal ofthe Periodic Table, (B′) an organic compound-modified, clay, claymineral or ion-exchangeable layered compound, and (C′) at least onealuminoxy compound represented by the following general Formula (2):

[0010] wherein a plurality of R groups are each independently a C₁₋₁₀hydrocarbon group, and at least one of the R groups is a hydrocarbongroup having 2 or more carbon atoms; and y is an integer of 2 to 4.

[0011] The process for producing α-olefins comprises a step ofoligomerizing ethylene in the presence of the catalyst for producingα-olefins as defined above.

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] The present invention will be described in detail below.

[0013] [I] Catalyst for Polymerization of Vinyl Compounds

[0014] The catalyst for polymerizing vinyl compounds according to thepresent invention comprises (A) a complex of Group 4 to 10 transitionmetal of the Periodic Table, (B) a clay, clay mineral orion-exchangeable layered compound, and (C) at least one aluminoxycompound represented by the following general Formula (1):

[0015] wherein a plurality of R groups are each independently a C₁₋₁₀hydrocarbon group, and at least one of the R groups is a hydrocarbongroup having 2 or more carbon atoms; and x is an integer of 2 or more.

[0016] The respective components of the catalyst for polymerizing vinylcompound are explained below.

[0017] Component (A)

[0018] The component (A), generally called a main catalyst, is a complexof Groups 4 to 10 transition metal of the Periodic Table. Examples ofthe transition metal complexes include metallocene complexes of Group 4to 6 transition metals and chelate complexes of Group 4 to 10 transitionmetals.

[0019] As the metallocene complexes, there may be used those known inthe arts. Examples of the metallocene complexes include transition metalcomplexes containing one or two ligands selected from cyclopentadienyl,substituted cyclopentadienyl, indenyl and substituted indenyl, as wellas transition metal complexes having its ligand geometrically confined,as described in Japanese Patent Application Laid-Open Nos. 58-19309,61-130314, 3-163088, 4-300887, 4-211694 and 1-502036. The transitionmetal of the transition metal complexes is preferably zirconium,titanium or hafnium.

[0020] Specific examples of the metallocene complexes includecyclopentadienyl zirconium trichloride, pentamethylcyclopentadienylzirconium trichloride, bis(cyclopentadienyl) zirconium dichloride,bis(pentamethylcyclopentadienyl) zirconium dichloride,bis(cyclopentadienyl) zirconium dialkyl, indenyl zirconium trichloride,bis(indenyl) zirconium dichloride, dimethylsilylene-bis(indenyl)zirconium dichloride, (dimethylsilylene) (dimethylsilylene)-bis(indenyl)zirconium dichloride, (dimethylsilylene)-bis(2-methyl-4-phenylindenyl)zirconium dichloride, (dimethylsilylene)-bis(benzoindenyl) zirconiumdichloride, ethylene-bis(indenyl) zirconium dichloride, (ethylene)(ethylene)-bis(indenyl) zirconium dichloride, (ethylene)(ethylene)-bis(3-methylindenyl) zirconium dichloride, (ethylene)(ethylene)-bis(4,7-dimethylindenyl) zirconium dichloride,1,2-ethanediyl(t-butylamido)(tetramethyl-η5-cyclopentadienyl) zirconiumdichloride,dimethylsilylene(t-butylamido)(tetramethyl-η5-cyclopentadienyl)zirconium dichloride,1,2-ethanediyl(methylamido)(tetramethyl-η5-cyclopentadienyl) zirconium dichloride, andthose obtained by replacing the zirconium of the above complexes withtitanium or hafnium.

[0021] Preferred complexes of Group 4 to 10 transition metal of thePeriodic Table may include metal complexes represented by the followingFormulas (3) and (4):

L¹L²M¹X¹ _(m)Y¹ _(n)  (3)

L¹L²L³M¹X¹ _(m)Y¹ _(n)  (4)

[0022] In the Formulas (3) and (4), M¹ is a Group 4 to 10 transitionmetal of the Periodic Table, preferably titanium, zirconium, hafnium,vanadium, chromium, iron, cobalt, nickel, palladium or platinum, andmore preferably titanium, zirconium, iron, cobalt or nickel.

[0023] L¹ to L³ are each independently a ligand capable of bonding tothe transitional metal M¹ via a heteroatom. L¹ and L² of Formula (3) orL¹ to L³ of Formula (4) are preferably bonded to each other to form aring. Examples of the heteroatoms include nitrogen, oxygen and sulfur.Of these, nitrogen and oxygen are preferable. The nitrogen preferablyforms an unsaturated bond with carbon, and more preferably forms —C═N—structural units called imine.

[0024] X¹ and Y¹ may be the same or different, and each represents acovalent- or ion-bonding ligand such as hydrogen; halogen; C₁₋₂₀preferably C₁ hydrocarbon group; C₁₋₂₀ preferably C₁₋₁₀ alkoxy; amino;C₁₋₂₀ preferably C₁₋₁₂ phosphorus-containing hydrocarbon group such asdiphenylphosphino; C₁₋₂₀, preferably C₁₋₁₂ silicon-containinghydrocarbon group; or halogen-containing boride anion such as BF₄ ⁻.Preferred are halogen and C₁₋₂₀ hydrocarbon group. A plurality of X¹groups and a plurality of Y¹ groups may be respectively the same ordifferent from each other.

[0025] Each of m and n is independently 0 or a positive integer, and thesum of m and n is 0, 1, 2 or 3 depending on the valence of M¹.

[0026] Although not particularly limited, the transition metal complexesrepresented by Formula (3) are preferably chelate complexes havingoxygen or nitrogen as the coordinating element. An example of thechelate complexes having nitrogen coordinated to metal is adiimine-containing complex compounds represented by the followingFormula (5):

[0027] wherein M² is a Group 8 to 10 transition metal of the PeriodicTable; R¹ and R⁴ are each independently C₁₋₂₀ aliphatic hydrocarbongroup, phenyl or C₇₋₂₀ aromatic group having a hydrocarbon group on itsaromatic ring; R² and R³ are each independently hydrogen or C₁₋₂₀hydrocarbon group, and may be bonded together to from a ring; X¹ and Y¹may be the same or different and are each a covalent- or ion-bondinggroup, and a plurality of X¹ groups and a plurality of Y¹ groups may berespectively the same or different; and m and n are each 0 or a positiveinteger, and the sum of m and n is 0, 1, 2 or 3 depending on the valenceof M².

[0028] In the above Formula (5), M² is particularly preferably nickeland X¹ and Y¹ are each preferably halogen or C₁₋₂₀ hydrocarbon group,and more preferably chlorine or methyl. C₁₋₂₀ Aliphatic hydrocarbongroup for R¹ and R⁴ may include C₁₋₂₀ straight-chain or branched alkyland C₃₋₂₀ cycloalkyl such as methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, s-butyl, t-butyl, pentyl, hexyl, octyl, decyl,tetradecyl, hexadecyl, octadecyl, cyclopentyl, cyclohexyl, andcyclooctyl. Cycloalkyl may have a suitable substituent such as loweralkyl on its ring. Examples of C₇₋₂₀ aromatic group which has ahydrocarbon group on the aromatic ring include those having one or moreC₁₋₁₀ straight-chain, branched or cyclic alkyls on the aromatic ringsuch as phenyl and naphthyl. Preferred R¹ and R⁴ are aromatic groupshaving a hydrocarbon group on the aromatic ring, and2,6-diisopropylphenyl is particularly preferable. R¹ and R⁴ may be thesame or different from each other.

[0029] C₁₋₂₀ Hydrocarbon group for R² and R³ may include C₁₋₂₀straight-chain or branched alkyl, C₃₋₂₀ cycloalkyl, C₆₋₂₀ aryl, C₇₋₂₀arylalkyl. Examples for C₁₋₂₀ straight-chain or branched alkyl and C₃₋₂₀cycloalkyl are the same as those mentioned above. C₆₋₂₀ Aryl may bephenyl, tolyl, xylyl, naphthyl, methylnaphthyl, etc. C₇₋₂₀ Arylalkyl maybe benzyl, phenethyl, etc. R² and R³ may be the same or different fromeach other, and may be bonded to each other to form a ring.

[0030] Specific examples of the complex compounds represented by Formula(5) are shown below by Formulae [1] to [12].

[0031] The transition metal complexes represented by Formula (4) arepreferably nitrogen-containing iron, cobalt or nickel chelate complexes.Examples thereof are described in J. Am. Chem. Soc., 1998, 120,4049-4050, Chem. Commun. 1998, 849-850, WO 98/27124, WO 99/02472 and WO99/12981.

[0032] For example, the transition metal complex represented by Formula(4) may be a complex represented by the following Formula (6):

[0033] wherein M² is a Group 8 to 10 transition metal of the PeriodicTable; R⁵ to R⁹ are each independently hydrogen, halogen, hydrocarbongroup, substituted hydrocarbon group or heteroatom-containinghydrocarbon group, and may be bonded to each other to form a ring wheneach represents the hydrocarbon group; R¹⁰ and R¹¹ are eachindependently C₁₋₁₆₀ aliphatic hydrocarbon group or C₇₋₁₆₀ aromaticgroup having a hydrocarbon group on the aromatic ring; X¹ and Y¹ may bethe same or different and are each a covalent- or ion-bonding group, anda plurality of X¹ groups and a plurality of Y¹ groups may berespectively the same or different from each other; and m and n are each0 or a positive integer and the sum of m and n is 0, 1, 2 or 3 dependingon the valence of M².

[0034] In the above Formula (6), the hydrocarbon groups for R⁵ to R⁹ mayinclude, for example, C₁₋₃₀ straight-chain or branched alkyl; C₃₋₃₀cycloalkyl; C₆₋₃₀ aryl; C₇₋₃₀ arylalkyl; etc. Specific examples of theC₁₋₃₀ straight-chain or branched alkyl include methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, different isomericpentyl groups, different isomeric hexyl groups, different isomeric octylgroups, different isomeric decyl groups, different isomeric tetradecylgroups, different isomeric hexadecyl groups, different isomericoctadecyl groups, etc. Specific examples of the C₃₋₃₀ cycloalkyl includecyclopentyl, cyclohexyl, cyclooctyl, etc. The cycloalkyl may have asuitable substituent such as lower alkyl on its ring. Specific examplesof the C₆₋₃₀ aryl include phenyl, tolyl, xylyl, naphthyl,methylnaphthyl, etc. Specific examples of the C₇₋₃₀ arylalkyl includebenzyl, phenethyl, etc.

[0035] In the above Formula (6), the C₁₋₁₆₀ aliphatic hydrocarbon groupfor R¹⁰ and R¹¹ may be the same as C₁₋₃₀ straight-chain or branchedalkyl groups and C₃₋₃₀ cycloalkyl groups for R⁵ to R⁹. The C₇₋₁₆₀aromatic groups having a hydrocarbon group on the aromatic rings mayinclude, for example, phenyl and naphthyl having one or more C₁₋₁₀straight-chain or branched alkyls or cyclic alkyls on their aromaticrings. R¹⁰ and R¹¹ are preferably an aromatic group having a hydrocarbongroup on its aromatic ring, and more preferably 2-methylphenyl and2,4-dimethylphenyl.

[0036] M², X¹, Y¹, m and n in Formula (6) are the same as defined in theFormula (5). Preferred M² is iron, cobalt or nickel. X¹ and Y¹ arepreferably halogen or C₁₋₂₀ hydrocarbon group, and more preferablychlorine or methyl.

[0037] Specific examples of the transition metal compound represented byFormula (6) may include iron or cobalt complexes having a ligand such as2,6-diacetylpyridine bisimine compound, 2,6-diformylpyridine bisiminecompound, 2,6-dibenzoylpyridine bisimine compound, etc. Particularlypreferred are iron complexes having 2,6-diacetylpyridine bisiminecompound as a ligand. Such complexes may be metal complexes representedby the following Formula (7):

[0038] wherein M² is a Group 8 to 10 transition metal of the PeriodicTable; R⁵ to R⁹ and R¹² to R²¹ are each independently hydrogen, halogen,hydrocarbon group, substituted hydrocarbon group orheteroatom-containing hydrocarbon group, and any two adjacent groups ofR¹² to R²¹ may be bonded to each other to form a ring; X¹ and Y¹ may bethe same or different and are each covalent- or ion-bonding group, and aplurality of X¹ groups and a plurality of Y¹ groups may be respectivelythe same or different from each other; and m and n are each 0 or apositive integer and the sum of m and n is 0, 1, 2 or 3 depending on thevalence of M².

[0039] R⁵ to R⁹ and R¹² to R²¹ of Formula (7) are each independentlyhydrogen, halogen, hydrocarbon group, substituted hydrocarbon group orheteroatom-containing hydrocarbon group. Examples of halogen includefluorine, chlorine, bromine and iodine. Examples of the hydrocarbongroups include C₁₋₃₀ hydrocarbon groups. Specific examples thereofinclude C₁₋₃₀ straight-chain hydrocarbon groups such as methyl, ethyland n-propyl; C₃₋₃₀ branched hydrocarbon groups such as isopropyl,s-butyl and t-butyl; and C₃₋₃₀ alicyclic hydrocarbon groups such ascyclopentyl and cyclohexyl; and C₆₋₃₀ aromatic hydrocarbon groups suchas phenyl and naphthyl. The substituted hydrocarbons are those obtainedby substituting one or more hydrogen atoms of the above hydrocarbongroups with suitable substituents, e.g., C₁₋₃₀ substituted hydrocarbongroups. Examples of the substituents include hydrocarbon group, halogen,heteroatom-containing hydrocarbon group, etc. The hydrocarbon group asthe substituent may be the same as defined above. Examples of theheteroatoms include nitrogen, oxygen, sulfur, etc. The substitutedhydrocarbon groups may contain a heteroaromatic ring. Theheteroatom-containing hydrocarbon group may be alkoxy represented by—OR²⁵, amino represented by —NR²⁵ ₂ or silyl represented by —SiR²⁵ ₃,wherein R²⁵ is the hydrocarbon group as mentioned above.

[0040] R¹² may be a primary, secondary or tertiary carbon group. WhenR¹² is a primary carbon group, zero to two of R¹⁶, R¹⁷ and R²¹ may be aprimary carbon group and the remainder thereof may be hydrogen. When R¹²is a secondary carbon group, zero or one of R¹⁶, R¹⁷ and R²¹ may be aprimary or secondary carbon group and the remainder may be hydrogen.When R¹² is a tertiary carbon group, R¹⁶, R¹⁷ and R²¹ may be hydrogen.

[0041] Preferably, when R¹² is a primary carbon group, zero to two ofR¹⁶, R¹⁷ and R²¹ is a primary carbon group and the remainder ishydrogen. When R¹² is a secondary carbon group, zero or one of R¹⁶, R¹⁷and R²¹ is a primary or secondary carbon group and the remainder ishydrogen. When R¹² is a tertiary carbon group, R¹⁶, R¹⁷ and R²¹ are eachhydrogen. Two adjacent groups of R¹² to R²¹ may be bonded to each otherto form a ring.

[0042] M², X¹, Y¹, m and n in Formula (7) are the same as defined inFormula (6). Preferred M² is iron, cobalt or nickel, and iron isparticularly preferred. X¹ and Y¹ are preferably halogen (morepreferably chlorine) or C₁₋₂₀ hydrocarbon group (more preferablymethyl).

[0043] The following combination of the substituents is preferable inFormula (7).

[0044] R⁸ and R⁹ are each methyl or hydrogen; and/or R⁵, R⁶ and R⁷ areall hydrogen; and/or R¹³, R¹⁴, R¹⁵, R¹⁷, R¹⁸, R¹⁹ and R²⁰ are allhydrogen; and/or R¹² and R²¹ are each independently methyl, ethyl,propyl or isopropyl, preferably both are methyl or ethyl; and/or X¹ andY¹ are each monovalent anion, preferably selected from halide andcyanide.

[0045] The following combinations of the substituents are alsopreferable. Namely, when R¹² is a primary carbon group, R¹⁶ is a primarycarbon group and R¹⁷ and R²¹ are each hydrogen. Alternatively, when R¹²is a secondary carbon group, R¹⁶ is a primary or secondary carbon group,preferably a secondary carbon group and R¹⁷ and R²¹ are each hydrogen.When R¹² is a tertiary carbon group, R¹⁶, R¹⁷ and R²¹ are each hydrogen.

[0046] The following combinations of R⁵ to R⁹ and R¹² to R²¹ areparticularly preferable for Formula (7):

[0047] (a) R⁸=R⁹=methyl,R⁵=R⁶=R⁷=R¹³=R¹⁴=R¹⁵=R¹⁶=R¹⁷=R¹⁸=R¹⁹=R²⁰=hydrogen, and R¹²=R²¹=methyl;

[0048] (b) R⁸=R⁹=methyl,R⁵=R⁶=R⁷=R¹³=R¹⁴=R¹⁵=R¹⁶=R¹⁷=R¹⁸=R¹⁹=R²⁰=hydrogen, and R¹²=R²¹=ethyl;

[0049] (c) R⁸=R⁹=methyl,R⁵=R⁶=R⁷=R¹³=R¹⁴=R¹⁵=R¹⁶=R¹⁷=R¹⁸=R¹⁹=R²⁰=hydrogen, andR¹²=R²¹=isopropyl;

[0050] (d) R⁸=R⁹=methyl,R⁵=R⁶=R⁷=R¹³=R¹⁴=R¹⁵=R¹⁶=R¹⁷=R¹⁸=R¹⁹=R²⁰=hydrogen, and R¹²=R²¹=n-propyl;

[0051] (e) R⁸=R⁹=methyl, R⁵=R⁶=R⁷=R¹³=R¹⁵=R¹⁶=R¹⁷=R¹⁸=R²⁰=hydrogen, andR¹²=R¹⁴=R¹⁹=R²¹=methyl;

[0052] (f) R⁸=R⁹=methyl,R⁵=R⁶=R⁷=R¹³=R¹⁴=R¹⁵=R¹⁶=R¹⁷=R¹⁸=R¹⁹=R²⁰=hydrogen, and R¹²=R²¹=chlorine;and

[0053] (g) R⁸=R⁹=methyl,R⁵=R⁶=R⁷=R¹³=R¹⁴R¹⁵R¹⁶=R¹⁷=R¹⁸=R¹⁹=R²⁰=hydrogen, andR¹²=R²¹=trifluoromethyl.

[0054] In any of the above combinations, X¹ and Y¹ are each preferablyhalide or cyanide, and more preferably chlorine.

[0055] The transition metal compound represented by Formula (7) can beproduced, for example, by reacting a ketone compound represented by thefollowing Formula (8):

[0056] with an amine compound represented by H₂NR²² or H₂NR²³ whereinR²² and R²³ are

[0057] The reaction may be conducted in the presence of an organic acidsuch as formic acid as a catalyst. The compound obtained from the abovereaction may be then reacted with a halide of transition metal M², forexample a metal halide, to obtain the transition metal compound ofFormula (7).

[0058] The component (A) is preferably a complex of Group 8 to 10transition metal of the Periodic Table. Any of the transition metalcomplexes of Formulas (3) and (4) may be used as the complex of Group 8to 10 transition metal of the Periodic Table, and preferred arenitrogen-containing iron chelate complexes, nitrogen-containing cobaltchelate complexes and nitrogen-containing nickel chelate complexes.Also, the transition metal complexes may be used alone or in combinationof two or more.

[0059] Component (B)

[0060] The component (B) is a clay, clay mineral or ion-exchangeablelayered compound. The clay is a substance composed of agglomerated finehydrous silicate minerals, exhibits plasticity when kneaded with anappropriate amount of water and hardness when dried, and is sinteredwhen burnt at high temperatures. The clay mineral is a hydrous silicateforming a substantial part of clay. Either of clay or clay mineral,which may be natural or synthetic, may be used for preparing thecatalyst for polymerizing vinyl compounds.

[0061] The ion-exchangeable layered compound is preferably a compoundhaving a layered, crystalline structure comprising stacked, parallellayers of atoms bonded to each other by ion bonding, etc. Respectivelayers are weakly bonded and ions therein are exchangeable. Some clayminerals are ion-exchangeable, layered compounds.

[0062] Example of the clay mineral as the component (B) includephyllosilicate minerals such as phyllosilicic acid and a phyllosilicate.Natural phyllosilicates include smectite group minerals such asmontmorillonite, saponite and hectorite, mica group minerals such asillite and sericite, and mixed layered minerals of smectite group andmica group or mica group and vermiculite group. Synthesizedphyllosilicates include Tetrasilicon Fluoride Mica, Laponite andSmecton. In addition, non-clay, ionic crystalline compounds having alayered crystalline structure such as α-Zr(HPO₄)₂, γ-Zr(HPO₄)₂,α-Ti(HPO₄)₂ and γ-Ti(HPO₄)₂ may be used.

[0063] Other usable clays and clay minerals not classified into theion-exchangeable, layered compound include bentonite clay with a lowercontent of montmorillonite, Kibushi clay or gairome clay containingmontmorillonite with other major components, fibrous sepiolite orpalygorskite, and amorphous or low crystalline allophane or imogolite.

[0064] Of these substances as the component (B), preferred aresilicon-containing layered compounds such as phyllosilicate minerals andmica group minerals. Preferred phyllosilicate minerals are smectitegroup minerals such as montmorillonite (also referred to as purifiedbentonite and coarse bentonite according to contents, etc.), saponite,etc. Preferred mica group minerals are Tetrasilicon Fluoride Mica knownas synthesized mica, etc. Tetrasilicon Fluoride Mica is generally in theform of non-swelled or swelled micas, and preferred are swelled micas.In the present invention, the combination of iron chelate complex as thecomponent (A) and smectite or mica as the component (B) is preferablyused.

[0065] The component (B) is preferably in the form of particle having avolume average particle size of 3 μm or less. Particles generally have aspecific size distribution. The particle of the component (B) preferablyhas a size distribution in which the volume average particle size is 10μm or less and the content of particles having a volume average particlesize of 3.0 μm or less is 10% by weight or more, more preferably a sizedistribution in which the volume average particle size is 10 μm or lessand the content of particles having a volume average particle size of1.5 μm or less is 10% by weight or more. The volume average particlesize and the content of particles of a given volume average particlesize may be determined by a laser transmission particle size analyzersuch as CIS-1 manufactured by Galai Production Ltd.

[0066] The component (B) may be pretreated with acids, alkalis, salts ororganic compounds. Of such pretreated component, those pretreated withquaternary ammonium salts, amine compounds, adducts of amine andBrønsted acid, or organosilane compounds are preferable in-view ofpolymerization activity.

[0067] The quaternary ammonium salts may be quaternary alkylammoniumsalts, quaternary arylammonium salts, quaternary arylalkylammoniumsalts, quaternary benzylammonium salts and heteroaromatic ammoniumsalts, although not specifically limited thereto. Examples of thequaternary alkylammonium salts include tetra-n-propylammonium chloride,tetrabutylammonium chloride, dimethyldicyclohexylammonium chloride,methyltri-n-octylammonium chloride, methyltris(2-ethylhexyl)ammoniumchloride, methyl-tri-n-decylammonium chloride,methyl-tri-n-octylammonium chloride, methyl-tri-n-dodecylammoniumchloride and dimethyl-di-n-octadecylammonium dichloride. Examples of thequaternary arylammonium salts include tetraphenylammonium chloride, etc.Examples of the quaternary arylalkylammonium salts includephenyltrimethylammonium chloride, dimethyldiphenylammonium chloride andmethyltriphenylammonium chloride. Examples of the quaternarybenzylammonium salts include dimethyldibenzylammonium chloride andmethyltribenzylammonium chloride. Examples of the heteroaromaticammonium salts include N-methyl-2-benzylpyridinium chloride,N-methyl-3-benzylpyridinium chloride, N-methyl-4-benzylpyridiniumchloride, N-methyl-2-phenylpyridinium chloride,N-methyl-3-phenylpyridinium chloride and N-methyl-4-phenylpyridiniumchloride. Bromides, fluorides and iodides corresponding to the abovechlorides may be used as the quaternary ammonium salts. In thequaternary ammonium salt, the ratio of the number of carbon atoms to thenumber of nitrogen atoms is preferably 8 or more. More preferred arequaternary ammonium salts having at least one aromatic ring-containinggroup such as the quaternary benzylammonium salts, quaternaryarylammonium salts and quaternary arylalkylammonium salts; andquaternary ammonium salts having two or more alkyl groups having 6 ormore carbon atoms such as dimetyldicyclohexylammonium chloride,methyltri-n-octylammonium chloride, methyltris(2-ethylhexyl)ammoniumchloride, methyltri-n-decylammonium chloride, methyltri-n-octylammoniumchloride, methyltri-n-dodecylammonium chloride anddimetyldi-n-octadecylammonium chloride. The quaternary ammonium salt isused in an amount of 0.001 to 2 mmol, preferably 0.01 to 1 mmol per unitweight (g) of the component (B) such as clay, etc.

[0068] Examples of the amine compounds include primary amines such asstearylamine and octylamine; secondary amines such asN-stearyl-N-methylamine and N-octyl-N-methylamine; and tertiary aminessuch as tribenzylamine, N,N-dibenzyl-N-phenylamine andN,N-dimethyl-N-phenylamine. The amine compound may be used in the formof an adduct with Brønsted acid. Examples of the Brønsted acids includehydrochloric acid, sulfuric acid and phosphoric acid. The adduct of theamine compound and the Brønsted acid is used in an amount of 0.01 to 10mmol, preferably 0.1 to 1 mmol per unit weight (g) of the component (B)such as clay, etc.

[0069] The organosilane compound is represented, although notparticularly limited, by the following Formula (9):

R²⁴ _(p)SiX² _(4-p)  (9)

[0070] wherein R²⁴ is hydrogen or a group having a carbon or siliconatom which is directly bonded to Si; X² is halogen or a group having anoxygen or nitrogen atom which is directly bonded to Si; p is an integerfrom 1 to 3, and a plurality of R²⁴ groups or X² groups, if any, may bethe same or different from each other.

[0071] The organosilane compound of Formula (9) includes polynuclearpolysiloxane, polysilazane and bis-silyl compound represented by Formula(10):

X² _(4-p)Si(CH₂)_(q)SiX² _(4-p)  (10)

[0072] wherein q is an integer from 1 to 10; X² and p are the same asdefined in Formula (9).

[0073] Examples of the organosilane compounds of Formula (9) includetrialkylsilyl chlorides, dialkylsilyl dichlorides, diarylsilyldichlorides and alkylarylsilyl dichloriodes such as trimethylsilylchloride, triethylsilyl chloride, triisopropylsilyl chloride,t-butyldimethylsilyl chloride, t-butyldiphenylsilyl chloride,phenethyldimethylsilyl chloride, dimethylsilyl dichloride, diethylsilyldichloride, diisopropylsilyl dichloride, di-n-hexylsilyl dichloride,dicyclohexylsilyl dichloride, docosylmethylsilyl dichloride,bis(phenethyl)silyl dichloride, methylphenethylsilyl dichloride,diphenylsilyl dichloride, dimesitylsilyl dichloride and ditolylsilyldichloride.

[0074] Other examples of the organosilane compounds of Formula (9)include silyl halides obtained by substituting chlorine of the abovecompounds with another halogen; disilazanes such asbis(trimethylsilyl)amide, bis(triethylsilyl) amide,bis(triisopropylsilyl) amide, bis(dimethylethylsilyl)amide,bis(diethylmethylsilyl)amide, bis(dimethylphenylsilyl)amide,bis(dimethyltolylsilyl)amide and bis(dimethylmenthylsilyl)amide;trialkylsilyl hydroxides such as trimethylsilyl hydroxide, triethylsilylhydroxide, triisopropylsilyl hydroxide, t-butyldimethylsilyl hydroxideand phenethyldimethylsilyl hydroxide; polysilanols known as aperalkylpolysiloxypolyol; bissilyl compounds such asbis(methyldichlorosilyl)methane, 1,2-bis(methyldichlorosilyl)ethane,bis(methyldichlorosilyl)octane and bis(triethoxysilyl)ethane; andhydride-containing silanes such as dimethylchlorosilane,(N,N-dimethylamino)dimethylsilane and diisobutylchlorosilane.

[0075] Examples of the organosilane compounds represented by Formula(10) include bissilyl compounds such as bis(methyldichlorosilyl)methane,1,2-bis(methyldichlorosilyl)ethane, bis(methyldichlorosilyl)octane andbis(triethoxysilyl)ethane. The polynuclear polysiloxane may be cyclicpolysiloxanes such as 1,3,5,7-tetramethylcyclotetrasiloxane,1,3,5,7-tetraethylcyclotetrasiloxane and1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclotetrasiloxane; and linearpolysiloxanes such as1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane. Examples of thepolysilazane include disilazanes such as bis(trimethylsilyl) amide,bis(triethylsilyl) amide, bis(triisopropylsilyl) amide,bis(dimethylethylsilyl) amide, bis(diethylmethylsilyl) amide,bis(dimethylphenylsilyl)amide, bis(dimethyltolylsilyl)amide andbis(dimethylmenthylsilyl)amide.

[0076] The organosilane compounds may be used alone or in combination oftwo or more.

[0077] Of these organosilane compounds, preferred are those having atleast one alkyl group (R²⁴) such as alkylsilyl halides, especiallydiaklylsilyl halides. The pretreatment of the component (B) with theorganosilane compound is effectively conducted in the presence of water.In this case, water allows the coarse particles of clay, etc. to befinely dispersed, and changes the layered structure of clay, therebyenhancing the contact efficiency of the organosilane compound with clay,etc. Namely, water increases the distance between crystalline layers ofclay, etc. to promote the reaction between the organosilane compound andclay, etc. The organosilane compound is used 0.001 to 1000 mol,preferably 0.01 to 100 mol in terms of silicon atom per one kilogram ofthe component (B).

[0078] The pretreatment of the component (B) may be performed, forexample, by the following method. The clay, clay mineral orion-exchangeable layered compound is dispersed in water to prepare anaqueous dispersion into which a quaternary ammonium salt, an amine saltor Brønsted acid adduct thereof, or an organosilane compound is thenadded, followed by heating the mixture. The resulting slurry(hydrophobicized product) was filtered, and the obtained filter cake isdried.

[0079] Preferably, the component (B) is pretreated with the quaternaryammonium salt. Preferred examples of the component (B) suitablypretreated with the quaternary ammonium salt are those having a highcapability of adsorbing the quaternary ammonium salt, or those having ahigh capability of producing a layered compound (also referred to as anintercalation compound) by the reaction with clay, etc. For example,clays and clay minerals are preferable. More specifically, the component(B) is preferably phyllosilicate minerals, more preferably smectite, andmost preferably montmorillonite. Tetrasilicon fluoride mica ispreferable as the synthesized phyllosilicate.

[0080] Component (C)

[0081] The component (C) is an aluminoxy compound represented by thefollowing Formula (1):

[0082] In the above Formula (1), a plurality of R groups are eachindependently C₁₋₁₀ hydrocarbon group, and at least one of the R groupsis a hydrocarbon group having 2 or more carbon atoms. Apart of the Rgroups may be methyl, but a majority (at least one half) of the R groupsare preferably hydrocarbon groups having 2 or more carbon atoms.Examples of C₁₋₁₀ hydrocarbon groups include straight-chain hydrocarbongroups such as methyl, ethyl, n-propyl and n-hexyl; and branchedhydrocarbon groups such as isopropyl, isobutyl and t-butyl. Examples ofthe hydrocarbon groups having 2 or more carbon atoms includestraight-chain hydrocarbon groups such as ethyl, n-propyl and n-hexyl;and branched hydrocarbon groups such as isopropyl, isobutyl and t-butyl.Preferred R is ethyl or isobutyl in view of higher activity of theobtained catalyst. The suffix x is an integer of 2 or more, usually 2 to100, preferably 2 to 50, more preferably 2 to 10, and most preferably 2to 4. When x is 2 to 4, the obtained catalyst exhibits a higheractivity. Most preferred is an aluminoxy compound wherein R is ethyl orisobutyl and x is 2 to 4, and specifically a tetraethyl dialuminoxane,pentaethyl trialuminoxane and tetraisobutyl dialuminoxane.

[0083] The aluminoxy compounds are preferably soluble in saturatedhydrocarbon solvents such as n-hexane, n-heptane and cyclohexane in viewof good handling ability and higher catalytic activity.

[0084] The aluminoxy compound may be produced by reacting atrialkylaluminum compound with water, or by hydrolyzing dialkylaluminumhalide. The aluminoxy compound prepared by these methods sometimescontains an unreacted organoaluminum compound or a cyclic aluminoxycompound. In the present invention, although the component (C) is mainlythe aluminoxy compound, those containing such an unreactedorganoaluminum compound and cyclic aluminoxy compound may also be usedas the component (C).

[0085] Of these aluminoxy compounds represented by the Formula (1),preferred are those produced by reacting the organoalumium compound withwater.

[0086] Next, the process for producing the catalyst for polymerizingvinyl compounds according to the present invention is described. Thecatalyst for polymerizing vinyl compounds is prepared by contacting thecomponents (A), (B) and (C) with each other. The components (A) and (B)may be first contacted with each other, and then the component (C) maybe contacted with the components (A) and (B). The component (B)dehydrated in advance is preferably contacted with component (A) in viewof improved activity of the obtained catalyst. The contact temperatureis room temperature, preferably from room temperature to 100° C., andthe contact time is 10 minutes or more, preferably 15 minutes or more,more preferably one hour or more. The contact is preferably conducted inthe presence of a highly polar solvent. The higher the polarity of thesolvent, the higher the efficiency of contact between the components,thereby shortening the contact time. Examples of the solvents includearomatic hydrocarbons such as toluene and xylene.

[0087] The amount of the transition metal complex used as the component(A) is 0.1 to 1000 μmol, preferably 1 to 100 μmol, and the amount of thecomponent (C) is 0.01 to 20 mmol, preferably 0.1 to 10 mmol, each basedon unit weight (g) of the component (B) such as clay, etc.

[0088] [II] Process for Production of Vinyl Polymers

[0089] In the process for the production of vinyl polymers according tothe present invention, a vinyl compound is polymerized in the presenceof the above catalyst optionally containing an organometallic compound(D). Examples of the organometallic compounds are organoaluminumcompounds, organomagnesium compounds, organolithium compounds andorganozinc compounds. In view of low costs and easy availability,preferred are the organoaluminum compounds exemplified bytrialkylaluminums such as trimethylaluminum, triethylaluminum,tripropylaluminum, triisobutylaluminum and tri-t-butylaluminum; halogen-or alkoxy-containing alkylaluminums such as dimethylaluminum chloride,diethylaluminum chloride, dimethylaluminum methoxide and diethylaluminumethoxide; and methylalumoxane. Of these organoaluminum compounds,preferred is the trialkylaluminum, and more preferred istriisobutylaluminum. The amount of the optional component (D) is 0.1 to1000 mmol, preferably 0.5 to 50 mmol based on unit weight (g) of thecomponent (B) such as clay, etc.

[0090] Examples of the vinyl compounds are olefins, styrene, styrenederivatives, acrylic derivatives and vinyl esters of fatty acids.

[0091] Olefins are not strictly limited, and preferably α-olefins having2 to 20 carbon atoms. Examples of such α-olefins include ethylene,propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene,1-decene, 4-phenyl-1-butene, 6-phenyl-1-hexene, 3-methyl-1-butene,4-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-hexene,5-methyl-1-hexene, 3,3-dimethyl-1-pentene, 3,4-dimethyl-1-pentene,4,4-dimethyl-1-pentene and vinylcyclohexane. Examples of the otherolefins usable in the present invention include dienes such as1,3-butadiene, 1,4-pentadiene and 1,5-hexadiene; halogenated α-olefinssuch as hexafluoropropene, tetrafluoroethylene, 2-fluoropropene,fluoroethylene, 1,1-difluoroethylene, 3-fluoropropene, trifluoroethyleneand 3,4-dichloro-1-butene; and cyclic olefins such as cyclopenetene,cyclohexene, norbornene, 5-methylnorbornene, 5-ethylnorbornene,5-propylnorbornene, 5,6-dimethylnorbornene and 5-benzylnorbornene.Examples of the styrene derivatives include alkylstyrenes such asp-methylstyrene, p-ethylstyrene, p-propylstyrene, p-isopropylstyrene,p-butylstyrene, p-t-butylstyrene, p-phenylstyrene, o-methylstyrene,o-ethylstyrene, o-propylstyrene, o-isopropylstyrene, m-methylstyrene,m-ethylstyrene, m-isopropylstyrene, m-butylstyrene, mesitylstyrene,2,4-dimethylstyrene, 2,5-dimethylstyrene and 3,5-dimethylstyrene;alkoxystyrenes such as p-methoxystyrene, o-methoxystyrene andm-methoxystyrene; halogenated styrenes such as p-chlorostyrene,m-chlorostyrene, o-chlorostyrene, p-bromostyrene, m-bromostyrene,o-bromostyrene, p-fluorostyrene, m-fluorostyrene, o-fluorostyrene ando-methyl-p-fluorostyrene; trimethylsilylstyrene; vinyl benzoate; anddivinylbenzene. Examples of the acrylic derivatives include ethylacrylate, butyl acrylate, methyl methacrylate and ethyl methacrylate.Examples of the vinyl esters of fatty acids include vinyl acetate,isopropenyl acetate and vinyl acrylate.

[0092] In the process of the present invention, the vinyl compound maybe used alone or in combination of two or more. When thecopolymerization is intended, two or more of the above olefins may becombined arbitrarily.

[0093] In the process of the present invention, the above α-olefinshaving 2 to 20 carbon atoms may be copolymerized with another monomerexemplified by chain diolefins such as butadiene, isoprene,1,4-pentadiene and 1,5-hexadiene; polycyclic olefins such as norbornene,1,4,5,8-dimetano-1,2,3,4,4a,5,8,8a-octahydronaphthalene and2-norbornene; cyclic diolefins such as norbornadiene,5-ethylidenenorbornene, 5-vinylnorbornene and dicyclopentadiene; andunsaturated esters such as ethyl acrylate and methyl methacrylate.

[0094] The vinyl compound is preferably ethylene, propylene or styrene,and more preferably ethylene. The method for polymerizing vinylcompounds is not particularly limited and may be carried out by anyknown methods such as slurry polymerization, solution polymerization,vapor-phase polymerization, bulk polymerization and suspensionpolymerization, preferably by solution polymerization. In addition, thepolymerization may be carried out in either continuous manner orbatch-wise manner. As the solvent, if used, an aliphatic hydrocarbonsolvent such as butane, pentane, hexane, heptane, each including allisomers, and cyclohexane may be used. Of the above solvents, cyclohexaneis particularly preferable because the deterioration of the productpurity due to formation of alkylated by-product can be effectivelyavoided as compared with using aromatic hydrocarbon solvent such astoluene. The solvent may be used singly or in combination of two ormore. When the solvent is used, the amount of catalyst in terms of thecomponent (A) contained therein is generally 0.01 to 100 μmol,preferably 0.1 to 20 μmol per one liter solvent in view of obtainingsufficient reactivity.

[0095] The polymerization conditions are not specifically limited. Thereaction temperature is generally −78 to 200° C., preferably roomtemperature to 150° C. The reaction pressure is generally ordinarypressure to 15 MPa·G, preferably ordinary pressure to 5 MPa·G. Themolecular weight can be controlled by know methods, for example, bysuitably selecting the temperature and pressure. When the vinylcompounds are polymerized using the catalyst of the present invention,vinyl-terminated α-olefins (oligomer) having a number average molecularweight of 10,000 or less or polyolefins having a number averagemolecular weight of more than 10,000 can be efficiently produced withlow costs.

[0096] [III] Catalyst for Production of α-Olefin Oligomers

[0097] The catalyst for producing α-olefins comprises (A′) a complex ofGroup 8 to 10 transition metal of the Periodic Table, (B′) an organiccompound-modified, clay, clay mineral or ion-exchangeable layeredcompound, and (C′) at least one aluminoxy compound represented by thefollowing general Formula (2):

[0098] wherein a plurality of R groups are each independently C₁₋₁₀hydrocarbon group, and at least one of the R groups is a hydrocarbongroup having 2 or more carbon atoms; and y is an integer of 2 to 4.

[0099] When the complex of Group 8 to 10 transition metal of thePeriodic Table is used in combination with the organiccompound-modified, clay, clay mineral or ion-exchangeable layeredcompound, the respective catalyst components are rendered insoluble in areaction solvent (hydrocarbon), so that the catalyst is readilyseparated from the reaction mixture after completion of theoligomerization reaction without deactivation thereof.

[0100] Component (A′)

[0101] The complex of Group 8 to 10 transition metal of the PeriodicTable is preferably selected from chelate complexes represented by thegeneral Formulas (5) and (6). More preferred are chelate complexesrepresented by the general Formulas (5) and (6) in which M² is iron,cobalt or nickel; and X¹ and Y¹ are each halogen, especially chlorine,or C₁₋₂₀ hydrocarbon group, especially methyl. Example of the preferredR¹ to R⁴ groups and the preferred R⁵ to R¹¹ groups are the same asdescribed above.

[0102] Component (B′)

[0103] The component (B′) is prepared by modifying clay, clay mineral orion-exchangeable layered compound selected from those exemplified as thecomponent (B), with an organic compound. Examples of the organiccompounds used for the modification of the component (B) includequaternary ammonium salts, amine compounds, adducts of amine andBrønsted acid or organosilane compounds. Of these organic compounds, thequaternary ammonium salts and the organosilane compounds are preferred.

[0104] The clay, clay mineral or ion-exchangeable layered compound maybe modified with the organic compound in the following manner. The clay,clay mineral or ion-exchangeable layered compound is dispersed in waterto prepare an aqueous dispersion, into which the quaternary ammoniumsalt, the amine salt, the adduct of amine and Brønsted acid or theorganosilane compound is then added, followed by heating the mixture.The resulting slurry (hydrophobicized product) was filtered, and theobtained filter cake is dried.

[0105] For the modification of the clay, clay mineral orion-exchangeable layered compound, the quaternary ammonium salt is usedin an amount of 0.01 to 10 mmol, preferably 0.1 to 1 mmol; the aminesalt or the adduct of amine and Brønsted acid is used in an amount of0.01 to 10 mmol, preferably 0.1 to 1 mmol; and the organosilane compoundis used in an amount of 0.1 to 100 mmol, preferably 0.5 to 10 mmol, eachbased on one gram of the clay, etc.

[0106] Component (C′)

[0107] The component (C′) is the aluminoxy compound represented by thefollowing general Formula (2):

[0108] In Formula (2), R is the same as defined in Formula (1); and y isan integer of 2 to 4. A part of a plurality of R groups may be methyl,but a majority (at least one half) of the R groups are preferablyhydrocarbon groups having 2 or more carbon atoms.

[0109] The catalyst for producing α-olefins according to the presentinvention may be prepared by preliminarily contacting the components(A′) and (B′) and then contacting the component (C′) in a reactionsystem for oligomerization of ethylene, or by preliminarily contactingthe components (B′) and (C′) and then contacting the component (A′) withthe components (B′) and (C′). For example, the components to becontacted are dispersed in an aromatic hydrocarbon solvent such astoluene and xylene, and the resulting mixture is stirred at roomtemperature, preferably at a temperature of from room temperature to100° C., for 10 minutes or more, preferably 15 minutes or more, and morepreferably one hour or more.

[0110] In any of the above preparation methods, when the clay, claymineral or ion-exchangeable layered compound modified with the organiccompound is used, the components (A′) and (C′) are adsorbed into layersof the component (B′), so that the respective catalyst components arerendered insoluble in a reaction solvent (hydrocarbon) for theoligomerization. On the contrary, the use of a large amount of theconventional methylaluminoxane results in not only deterioratedcatalytic activity but also failure to keep the excess amount ofmethylaluminoxane in a solid state during the reaction. As a result, alarge amount of the methylaluminoxiane is transferred into liquid phasein the subsequent solid-liquid separation step, thereby causing problemssuch as deposition of metal component (aluminum compound) within adistiller. In order to prevent the catalyst components from being elutedinto liquid phase and improve the activity of the catalyst, it isessential to use the aluminoxy compound represented by Formula (2).

[0111] The component (C′) is used in an amount of 0.01 to 10 mmol,preferably 0.1 to 5 mmol in terms of aluminum atom per unit weight (g)of the component (B′). The component (A′) is used in an amount of 0.5 to100 μmol, preferably 1 to 20 μmol in terms of transition metal per unitweight (g) of the component (B′). When the amount of the component (A′)exceeds the above range, the component (B′) fails to adsorb the wholeamount of the component (A′), thereby causing the elution of thecomponent (A′) into liquid phase in the solid-liquid separation step.With such a formulation, the catalyst for the production of α-olefinsaccording to the present invention is still kept in a solid state evenafter completion of the oligomerization without the elution of thecatalyst components into liquid phase. As a result, the catalyst isreadily separated from the reaction solution by solid-liquid separation,thereby smoothly performing the subsequent purification of α-olefins bydistillation.

[0112] [IV] Process for Producing α-Olefins

[0113] In the process of the present invention, α-olefins (oligomers)may be produced by oligomerizing ethylene in the presence of thecatalyst containing the above components (A′), (B′) and (C′) andoptionally the organometallic compound (D).

[0114] The optional organometallic compound (D) is used in an amount of0.1 to 1,000 mmol, preferably 0.5 to 50 mmol based on unit weight (g) ofthe component (B′).

[0115] The oligomerization of the α-olefin monomers may be carried outby any known methods such as slurry polymerization, solutionpolymerization, vapor-phase polymerization, bulk polymerization andsuspension polymerization, preferably by solution polymerization. Inaddition, the oligomerization may be carried out in either continuousmanner or batch-wise manner. As the solvent for the oligomerization, analiphatic hydrocarbon solvent such as butane, pentane, hexane, heptane,each including all isomers, and cyclohexane may be used. When thesolvent is used, the amount of the catalyst in terms of the component(A′) is generally 0.01 to 100 μmol, preferably 0.1 to 20 μmol per oneliter solvent.

[0116] The oligomerization conditions are not specifically limited. Thereaction temperature is generally 0 to 150° C., preferably roomtemperature to 150° C. The reaction pressure is generally ordinarypressure to 15 MPa·G, preferably ordinary pressure to 5 MPa·G. Theoligomer distribution during the oligomerization can be controlled byany know methods, for example, by suitably selecting the temperature andpressure. The oligomers are produced according to Schulz-Florydistribution rule. The oligomer distribution depends on K-value whichchanges from 0.4 to 0.8. When the K-value is 0.4, the content of1-butene becomes higher, and when the K-value is 0.8, the content ofhigh-molecular weight wax becomes higher. In the present invention, theK value is preferably 0.5 to 0.7.

[0117] After completion of the oligomerization, the reaction mixture issubjected to solid-liquid separation. The solid-liquid separation may bepractically and simply carried out by centrifugally separating thereaction mixture into a solid phase (catalyst and by-produced polymer)and a liquid phase (α-olefins and oligomerization solvent). Thecentrifugal force and the centrifugal separation time required for thesolid-liquid separation varies depending upon kind and particle size ofthe component (B′), and usually 10 to 10,000 G and 1 second to 10minutes, respectively. For example, when montmorillonite having anaverage particle size of 0.1 μm is used as the component (B′), thesolid-liquid separation of the reaction mixture is sufficientlyaccomplished by the centrifugal separation at a centrifugal force of 125G for one minute.

[0118] When the solid-liquid separation is carried out at 100° C. orhigher, the by-produced polymer is dissolved in the reaction solvent,resulting in undesirable precipitation of the by-produced polymer in thesubsequent solvent removal and oligomer purification by distillation.Accordingly, the solid-liquid separation is preferably carried out at 0to 90° C., more preferably 20 to 80° C.

[0119] In the process of the present invention for producing α-olefins,vinyl-terminated α-olefins (oligomers) having a number average molecularweight of 10,000 or less are efficiently produced with low costs.

[0120] The present invention will be described in more detail withreference to the following examples. However, it should be noted thatthe following examples are only illustrative and not intended torestrict the scope of the present invention thereto.

EXAMPLE 1

[0121] (1) Preparation of Clay-Quaternary Ammonium Salt Slurry A

[0122] Into a 2-liter flask containing one liter of distilled water, 2.5g of Na-montmorillonite (BEN-GEL, available from Hojun Yoko, Co., Ltd.)were slowly added under stirring. Thereafter, stirring was continued fortwo hours at room temperature to prepare a clay-water colloidalsolution. After heating the clay-water colloidal solution to 60° C., anaqueous solution prepared by dissolving 0.792 g (2 mmol) ofbenzylcetyldimethyl ammonium chloride in 100 ml of water was addedthereto. After the addition, the mixture was stirred for one hour at thesame temperature. The resultant slurry was filtered under heatingthrough a pressure filter. The separated solid product was vacuum-driedat room temperature to obtain 3.1 g of clay-quaternary ammonium saltcomposite.

[0123] A 300-ml Schlenk tube was charged with 1.0 g of theclay-quaternary ammonium salt composite and 200 ml of toluene. Afterheating to 100° C., the mixture was stirred for one hour at the sametemperature and cooled to obtain a clay slurry. The supernatant of theclay slurry was discarded by a cannula, and the volume of the slurry wasadjusted to 50 ml by adding toluene to obtain the clay-quaternaryammonium salt composite slurry A (clay-quaternary ammonium saltcomposite content: 20 mg/ml).

[0124] (2) Preparation of Catalyst Slurry A

[0125] Into 20 ml of toluene, was suspended 0.088 g (200 μmol) of apyridinebisimine iron complex, [2,6-[(2,4-C₆H₃Me₂)N═C(Me)]₂C₅H₃N]FeCl₂,which was prepared according to the method described in J. Am. Chem.Soc., 1998, 4049 and Chem. Commun., 1998, 849, thereby preparing acomplex slurry A (complex content: 10 μmol/ml). In a Schlenk tube, 5.0ml of the clay-quaternary ammonium salt composite slurry A and 0.2 ml ofthe complex slurry A were mixed and stirred for two hours at roomtemperature to prepare a catalyst slurry A.

[0126] (3) Oligomerization

[0127] Into a 1.6-liter autoclave of 50° C., 400 ml of dry cyclohexane,0.13 ml of a toluene solution (Al content: 1.0 mol/liter) oftetraisobutyldialuminoxane, [(CH₃)₂CHCH₂]₂AlOAl[CH₂CH(CH₃)₂]₂ (compoundrepresented by Formula (1) in which all R groups are isobutyl and x is2, or by Formula (2) in which all R groups are isobutyl and y is 2), andall of the catalyst slurry A prepared above were successively added innitrogen stream (molar ratio between metals: Al/Fe=65). Thereafter,ethylene was pumped into the autoclave to keep the reaction pressure at0.8 MPa·G. Thirty minutes after starting the introduction of ethylene,the supply of ethylene was stopped and the reaction liquid was rapidlycooled by cooling water. After cooling and pressure release, 138.4 g(total yield) of the reaction product containing 0.82 g of solidcyclohexane insolubles, i.e., polymer and 137.5 g of cyclohexanesolubles were obtained. The total polymerization activity and thepolymerization activity for the cyclohexane solubles were 2476 kg/gFe/hand 2462 kg/gFe/h, respectively. ¹³C-NMR measurement showed that thepolymer obtained was a vinyl-terminated polymer. Gas chromatographicanalysis showed that 99% by weight of the cyclohexane solubles was avinyl-terminated, linear (α-olefin (hereinafter occasionally referred tomerely as “oligomer”). In the gas chromatographic analysis, OV-1 column(60 m) was used for determining the amount of oligomer and Ultra-2column (50 m) was used for determining the purity.

EXAMPLE 2

[0128] The oligomerization of ethylene was conducted in the same manneras in Example 1(3) except for changing the amount of the toluenesolution of tetraisobutyldialuminoxane,[(CH₃)₂CHCH₂]₂AlOAl[CH₂CH(CH₃)₂]₂, (Al content: 1.0 mol/liter) from 0.13ml to 0.25 ml.

[0129] As a result, 73.2 g (total yield) of the reaction productcontaining 0.59 g of solid cyclohexane insolubles, i.e., polymer and72.61 g of cyclohexane solubles were obtained. The total polymerizationactivity and the polymerization activity for the cyclohexane solubleswere 1311 kg/gFe/h and 1300 kg/gFe/h, respectively. ¹³C-NMR measurementshowed that the polymer obtained was a vinyl-terminated polymer.Further, the same Gas chromatographic analysis as in Example 1 showedthat 99% by weight of the cyclohexane solubles was a vinyl-terminated,linear α-olefin.

EXAMPLE 3

[0130] The oligomerization of ethylene was conducted in the same manneras in Example 1(3) except for changing the amount of the toluenesolution of tetraisobutyldialuminoxane,[(CH₃)₂CHCH₂]₂AlOAl[CH₂CH(CH₃)₂]₂, (Al content: 1.0 mol/liter) from 0.13ml to 0.50 ml.

[0131] As a result, 40.0 g (total yield) of the reaction productcontaining 0.46 g of solid cyclohexane insolubles, i.e., polymer and39.54 g of cyclohexane solubles was obtained. The total polymerizationactivity and the polymerization activity for the cyclohexane solubleswere 716 kg/gFe/h and 708 kg/gFe/h, respectively. ¹³C-NMR measurementshowed that the polymer obtained was a vinyl-terminated polymer.Further, the same Gas chromatographic analysis as in Example 1 showedthat 98% by weight of the cyclohexane solubles was a vinyl-terminated,linear α-olefin.

EXAMPLE 4

[0132] (1) Preparation of Clay-Quaternary Ammonium Salt Slurry B

[0133] Into a 300-ml Schlenk tube, were added 1.0 g of S-BEN 78 (organicbentonite available from Hojun Yoko Co., Ltd.; montmorillonitecontaining a quaternary ammonium salt having long-chain (C₁₆₋₁₈) alkylgroup) and 200 ml of toluene to prepare a clay dispersion. After heatingto 100° C., the resultant dispersion was stirred for one hour at thesame temperature and allowed to cool to obtain a clay slurry. Thesupernatant of the clay slurry was discarded by a cannula, and thevolume of the slurry was adjusted to 50 ml by adding toluene to obtainthe clay-quaternary ammonium salt composite slurry B (clay-quaternaryammonium salt composite content: 20 mg/ml).

[0134] (2) Preparation of Catalyst Slurry B

[0135] The catalyst slurry B was prepared in the same manner as inExample 1(2) except for using 5 ml of the clay-quaternary ammonium saltcomposite slurry B and 0.2 ml of the complex slurry A.

[0136] (3) Oligomerization

[0137] The oligomerization of ethylene was conducted in the same manneras in Example 3(2) except for using the catalyst slurry B instead of thecatalyst slurry A. As a result, 31.9 g (total yield) of the reactionproduct containing 0.32 g of solid cyclohexane insolubles, i.e., polymerand 31.58 g of cyclohexane solubles was obtained. The totalpolymerization activity and the polymerization activity for thecyclohexane solubles were 571 kg/gFe/h and 565 kg/gFe/h, respectively.¹³C-NMR measurement showed that the polymer obtained was avinyl-terminated polymer. Further, the same Gas chromatographic analysisas in Example 1 showed that 97% by weight of the cyclohexane solubleswas a vinyl-terminated, linear α-olefin.

EXAMPLE 5

[0138] The oligomerization of ethylene was conducted in the same manneras in Example 3(2) except for using a pentaisobutyltrialuminoxane,[(CH₃)₂CHCH₂]₂AlOAl[CH₂CH(CH₃)₂]OAl[CH₂CH(CH₃)₂]₂, (compound representedby Formula (1) in which all R groups are isobutyl and x is 3, or byFormula (2) in which all R groups are isobutyl and y is 3) instead ofthe tetraisobutyldialuminoxane, [(CH₃)₂CHCH₂]₂AlOAl[CH₂CH(CH₃)₂]₂. As aresult, 28.1 g (total yield) of the reaction product containing 0.32 gof solid cyclohexane insolubles, i.e., polymer and 27.78 g ofcyclohexane solubles were obtained. The total polymerization activityand the polymerization activity for the cyclohexane solubles were 503kg/gFe/h and 497 kg/gFe/h, respectively. ¹³C-NMR measurement showed thatthe polymer obtained was a vinyl-terminated polymer. Further, the sameGas chromatographic analysis as in Example 1 showed that 97% by weightof the cyclohexane solubles was a vinyl-terminated, linear α-olefin.

Comparative Example 1

[0139] The oligomerization of ethylene was conducted in the same manneras in Example 1(3) except for using 0.13 ml of a toluene solution (Alcontent: 1.0 mol/liter) of methylalumoxane (available from AlbemarleCorp.; a mixture of (CH₃)₂Al[OAl(CH₃)]_(n-1)CH₃ wherein n is 2 to 40 andn is 8 in average) instead of 0.13 ml of the toluene solution (Alcontent: 1.0 mol/liter) of tetraisobutyldialuminoxane,[(CH₃)₂CHCH₂]₂AlOAl[CH₂CH(CH₃)₂]₂. As a result, 4.8 g (total yield) ofthe reaction product containing 0.47 g of solid cyclohexane insolubles,i.e., polymer and 4.33 g of cyclohexane solubles were obtained. Thetotal polymerization activity and the polymerization activity for thecyclohexane solubles were 347 kg/gFe/h and 314 kg/gFe/h, respectively.¹³C-NMR measurement showed that the obtained polymer contained noterminal vinyl. Further, the same Gas chromatographic analysis as inExample 1 showed that 94% by weight of the cyclohexane solubles was avinyl-terminated, linear α-olefin.

Comparative Example 2

[0140] The oligomerization of ethylene was conducted in the same manneras in Example 3(2) except for using triisobutyl aluminum,[(CH₃)₂CHCH₂]₃Al, corresponding to a compound represented by Formula (1)in which all R groups are isobutyl and x is 1, or by Formula (2) inwhich all R groups are isobutyl and y is 1, instead of thetetraisobutyldialuminoxane, [(CH₃)₂CHCH₂]₂AlOAl[CH₂CH(CH₃)₂]₂. As aresult, 14.5 g (total yield) of the reaction product containing 0.27 gof solid cyclohexane insolubles, i.e., polymer and 14.23 g ofcyclohexane solubles were obtained. The total polymerization activityand the polymerization activity for the cyclohexane solubles were 259kg/gFe/h and 255 kg/gFe/h, respectively. ¹³C-NMR measurement showed thatthe obtained polymer contained no terminal vinyl. Further, the same Gaschromatographic analysis as in Example 1 showed that 97% by weight ofthe cyclohexane solubles was a vinyl-terminated, linear α-olefin.

EXAMPLE 6

[0141] Two 150-ml columns were respectively filled with 100 ml of thereaction solution obtained in Example 1, and set in a centrifugalseparator SCR18B manufactured by Hitachi Kosoku Reikyaku Enshinki Co.,Ltd. The separator was then operated at 5000 rpm (centrifugal force:3160 G) for one minute to centrifugally separate the reaction solution.As a result, the reaction solution was completely separated into aliquid phase and a solid phase to give a transparent supernatant and apasty semisolid. The supernatant was measured to determine the amountsof iron, aluminum, nitrogen and polymer contained therein. Specifically,the iron content was determined by analyzing a solution prepared byheat-treating the concentrated supernatant with hydrochloric acid usingan inductively coupled plasma atomic emission spectrometer (ICP-AES).The aluminum content was determined by dissolving the concentratedsupernatant in a mixed acid of concentrated sulfuric acid andhydrofluoric acid and subjecting the resultant solution to ICP-AESmeasurement. The nitrogen content was determined by measuring thesupernatant by a total nitrogen analyzer. The content of the by-producedpolymer dissolved in cyclohexane was expressed by the amount of theresidues which were obtained by concentrating the supernatant in aweighing bottle at room temperature, and vacuum-drying the concentrateat 150° C. for one hour.

[0142] As a result of the above measurements, it was confirmed that thesupernatant contained iron in an amount less than the lower detectablelimit (less than 0.1 ppm), 7 ppm of aluminum, nitrogen in an amount lessthan the lower detectable limit (less than 1 ppm) and 250 ppm of theby-produced polymer.

EXAMPLE 7

[0143] Two 150-ml columns were respectively filled with 100 ml of thereaction solution obtained in Example 1, and set in a centrifugalseparator. The separator was operated at 1000 rpm (125 G) for one minuteto centrifugally separate the reaction solution. As a result, thereaction solution was completely separated into a liquid phase and asolid phase to give a transparent supernatant and a pasty semisolid. Thesupernatant was examined in the same manner as in Example 6. The resultsshowed that the supernatant contained iron in an amount less than thelower detectable limit, 8 ppm of aluminum, nitrogen in an amount lessthan the lower detectable limit and 250 ppm of the by-produced polymer.

EXAMPLE 8

[0144] Two 150-ml columns were respectively filled with 100 ml of thereaction solution obtained in Example 1, and set in a centrifugalseparator. The separator was then operated at 570 rpm (30 G) for 3minutes to centrifugally separate the reaction solution. As a result,the reaction solution was completely separated into a liquid phase and asolid phase to give a transparent supernatant and a pasty semisolid. Thesupernatant was examined in the same manner as in Example 6. The resultsshowed that the supernatant contained iron in an amount less than thelower detectable limit, 12 ppm of aluminum, nitrogen in an amount lessthan the lower detectable limit and 330 ppm of the by-produced polymer.

Reference Example

[0145] The reaction solution obtained in Example 1 was stirred again,and allowed to stand for one minute to sample 300 ml of suspendedsupernatant. The thus sampled supernatant was concentrated and extractedwith ethanol. The extract was subjected to ICP-AES analysis to determinethe amount of iron and aluminum contained therein. An ethanol extractobtained in the same manner as above was analyzed by a total nitrogenanalyzer to determine the amount of nitrogen contained therein. Thecontent of the by-produced polymer was calculated by subtracting theweight of residues (clay) after baking the concentrated supernatant fromthe weight of dried product (polymer and clay) obtained by vacuum-dryingthe concentrated supernatant.

[0146] The results showed that the supernatant contained 11 ppm iron,1240 ppm of aluminum, 8 ppm of nitrogen and 4500 ppm of the by-producedpolymer.

INDUSTRIAL APPLICABILITY

[0147] Vinyl-terminated, linear α-olefins (oligomers) having a numberaverage molecular weight of 10,000 or less or polyolefins having anumber average molecular weight of larger than 10,000 can be efficientlyproduced with low costs by using the catalyst of the present invention.The oligomers can be used as comonomers for olefin polymerization forproducing LLDPE, etc. or materials for synthetic lubricant oils andcleaning agents.

[0148] In the catalyst for producing α-olefins according to the presentinvention, the catalyst components necessary for the oligomerization ofethylene are adsorbed between layers of the clay, clay mineral orion-exchangeable layered compound modified with the organic compound.Therefore, the catalyst is kept in a solid state even after theoligomerization, thereby facilitating the separation of the catalystfrom the reaction mixture. Further, since the separation of the catalystis accomplished without deactivation, the ligand of the transition metalcomplex is prevented from being dissociated from the center metal,thereby producing high-boiling ethylene oligomers at a high purity. Inaddition, the use of a specific aluminoxy compound in the catalystprevents aluminum compounds from dissolving into liquid phase andinhibits metal components from depositing within a distiller, resultingin facilitated operation of the apparatus.

1. A catalyst for polymerizing vinyl compounds, comprising (A) a complexof Group 4 to 10 transition metal of the Periodic Table, (B) a clay,clay mineral or ion-exchangeable layered compound, and (C) at least onealuminoxy compound represented by the general Formula (1):

wherein a plurality of r groups are each independently C₁₋₁₀ hydrocarbongroup and at least one of the r groups is a hydrocarbon group having 2or more carbon atoms; and x is an integer of 2 or more.
 2. The catalystaccording to claim 1, wherein a ligand of the component (A) is bonded tothe transitional metal via a heteroatom.
 3. The catalyst according toclaim 1 or 2, wherein the component (A) is a chelate complex of atransition metal selected from the group consisting of titanium,zirconium, hafnium, vanadium, chromium, nickel, cobalt, and iron.
 4. Thecatalyst according to any one of claims 1 to 3, wherein the component(B) is a silicon-containing, ion-exchangeable layered compound.
 5. Thecatalyst according to claim 1 or claim 2, wherein the component (A) isan iron chelate complex, and the component (B) is smectite or mica. 6.The catalyst according to any one of claims 1 to 5, wherein R of thecomponent (C) is ethyl or isobutyl.
 7. A process for producing vinylpolymers, comprising a step of polymerizing at least one vinyl compoundselected from the group consisting of olefins, styrene, styrenederivatives, acrylic acid derivatives and vinyl esters of fatty acids,in the presence of the catalyst as defined in any one of claims 1 to 6.8. The process according to claim 7, wherein the vinyl compound isethylene, propylene or styrene.
 9. The process according to claim 7 or8, wherein the polymerization of said vinyl compound is conducted in asaturated hydrocarbon compound as a polymerization solvent.
 10. Theprocess according to any one of claims 7 to 9, wherein the vinylpolymers are vinyl-terminated oligomers having a number averagemolecular weight of 10,000 or less.
 11. A catalyst for producingα-olefins, comprising (A′) a complex of Group 8 to 10 transition metalof the Periodic Table, (B′) an organic compound-modified clay, claymineral or ion-exchangeable layered compound, and (C′) at least onealuminoxy compound represented by the general Formula (2):

wherein a plurality of R groups are each independently C₁₋₁₀ hydrocarbongroup and at least one of the R groups is a hydrocarbon group having 2or more carbon atoms; and y is an integer of 2 to
 4. 12. The catalystaccording to claim 11, wherein a ligand of the component (A′) is bondedto the transitional metal via a heteroatom.
 13. The catalyst accordingto claim 11 or 12, wherein the component (A′) is a chelate complex of atransition metal selected from the group consisting of nickel, cobaltand iron.
 14. The catalyst according to any one of claims 11 to 13,wherein the component (B′) is a silicon-containing ion-exchangeablelayered compound modified with an organic compound.
 15. The catalystaccording to any one of claims 11 to 14, wherein the organic compoundused for modifying the clay, clay mineral or ion-exchangeable layeredcompound is at least one compound selected from the group consisting ofquaternary ammonium salts and organosilane compounds.
 16. The catalystaccording to claim 11 or 12, wherein the component (A′) is an ironchelate complex, and the component (B′) is an organic compound-modifiedsmectite or mica.
 17. The catalyst according to any one of claims 11 to16, wherein R of the component (C′) is ethyl or isobutyl.
 18. A processfor producing α-olefins, comprising a step of oligomerizing ethylene inthe presence of the catalyst as defined in any one of claims 11 to 17.19. The process according to claim 18, wherein the oligomerization isperformed in a saturated hydrocarbon as a polymerization solvent. 20.The process according to claim 18 or 19, wherein residue of the catalystand by-produced polymer are separated from a reaction product bysolid-liquid separation method.
 21. The process according to claim 20,wherein the solid-liquid separation method is a centrifugal separationmethod.
 22. The process according to claim 21, wherein the centrifugalseparation method is performed at a temperature of 100° C. or lower.